Method and apparatus for protecting radio frequency power amplifiers

Abstract

A power amplifier protection system to sense one or more operating conditions of a power amplifier and regulate the power of the input signal to the power amplifier as a response to one or more of the sensed operating conditions. This dynamic protection system may protect a power amplifier from failure by monitoring such operating conditions as power output and temperature and reducing the amplitude of the input signal if the power amplifier is operating beyond specified levels.

What is claimed is:  
     
       1. A method for protecting a power amplifier comprising: 
       sensing two or more operating conditions of a power amplifier selected from the group consisting of temperature, current and output voltage;  
       comparing the sensed temperature, current, and output voltage operating conditions to specified operating limits for the respective operating conditions; and  
       reducing the power of an input signal to the power amplifier if one or more of the operating conditions is beyond specified operating limits for the power amplifier.  
     
     
       2. The method of  claim 1  wherein the current is the amplifier current. 
     
     
       3. The method of  claim 1  wherein the current is the current through a transistor in the amplifier. 
     
     
       4. A method for protecting a power amplifier comprising: 
       sensing temperature, current and output voltage of the power amplifier;  
       comparing the sensed temperature, current, and output voltage operating conditions to specified operating limits for the respective operating conditions; and  
       reducing the power of an input signal to the power amplifier if one or more of the operating conditions is beyond specified operating limits for the power amplifier.  
     
     
       5. The method of  claim 4  wherein the current is the amplifier current. 
     
     
       6. The method of  claim 4  wherein the current is the current through a transistor in the amplifier. 
     
     
       7. A power amplifier protection system comprising: 
       a first sub-system to sense temperature, current, and output voltage operating conditions of a power amplifier; and  
       a second sub-system to regulate the power of an input signal to the power amplifier in response to the sensed temperature, current, and output voltage operating conditions exceeding specified operating limits, respectively, and  
       a third sub-system to compare the sensed temperature, current, and output voltage operating conditions of the power amplifier to specified operating limits, respectively.